1. Field of the Invention
This invention relates to a winder for a sheet material such as a film or the like, and more particularly, to a multi-shaft linear motion type winder for winding up a film or the like without using a turret.
2. Description of the Related Art
When a film being fed from the film making step is wound up on a winding core in a given length, roll changing is performed from the core having thereon the wound-up film to a new winding core.
Hitherto, a two-shaft (A,B) turret T as shown in FIGS. 4A to 4D, on which one shaft with fully-wound roll and the other shaft for a new winding core are installed together, or a multishaft turret has been used, and consequently, the roll changing work has been conducted by turning the turret T every time the winding process is finished.
That is, in the state illustrated in FIG. 4A, a shaft A is in the course of winding while a shaft B is being attached with a new winding core. A film F is wound via a guide roller onto a winding core on the shaft A by reason of a contact pressure of a touch roller 7. When the winding core of the shaft A is nearly fully wound thereon, the turret T is revolved as shown in FIG. 4B and a new core on the shaft B is shifted to a winding position. At that time, a cutting blade 9 is lowered to sever the film running between the shaft A and the shaft B, and the leading end of the film is wrapped around the new core on the shaft B. The winding-up process to the shaft A is thus stopped (FIG. 4C). Then, when a winding process to the new core on the shaft B is started, a new core is attached to the shaft A (FIG. 4D). In this way, one cycle of the winding process on the conventional turret is completed and the roll changing work for the next winding cycle is initiated.
With the foregoing winding that the roll changing work is conducted by the use of a turret, however, the size of the turret to be used is determined by a distance between centers of the winding shafts, depending upon the winding diameter of a roll, and hence, the higher the winding diameter is, the bigger the size of the turret. As a consequence, the winding machine is inevitably large-sized as the winding diameter is larger, and the production cost is vastly increased, as well.
Further, when the distance between the winding shafts is larger, the path length of the film upon roll changing is longer, which is responsible for the occurrence of neck-in and wrinkling of a film susceptible to extension. Again where the distance between the winding shafts is larger, the moving distance of a new winding core upon roll changing is larger, and consequently, it is difficult to change over to a next winding in a short cycle.
As for the aspect of transmissions of the turret lathe system, because the winding shafts are disposed inside the turret lathe and winding motors for respective shafts are installed outside the winding frame, their powers are necessitated to be transmitted to the winding shafts, relaying a main shaft of the turret during turning. This requires a large-sized tranmission device, brings about a large loss in the revolution mechanism, and raises a big problem in the control of transmission torques required for the winding shafts.
In order to cope with the aforesaid difficulties encountered in the conventional winder, the present invention has been accomplished by finding a linear motion type winder based on a different idea from the conventional turret system. Accordingly, it is an essential object of the invention to provide such a linear motion type winder that winding shafts can move linearly fore-and-aft and up-and-down and independently to the extent that no mutual interference is involved. A more particular object of the invention is to provide a linear motion type winder that enables it to eliminate the mechanical 1088 by simplifying the transmission device, to make the film path length upon roll changing shorter, to avoid the neck-in and wrinkling of an extensible film, and to diminish significantly the cycle of roll changing operations.